Electrical measuring instrument



July 15 1924.

J. W. RECORD ELECTRI CAL MEASURING INSTRUMENT Filed June 26, 1922 3Sheets$heet 1 IWENTQR; Qcoui 9 8 1 1 0 5 11 D R O C E R W July 15 1924.

ELECTRICAL MEASURING INSTRUMENT Filed June 26, 192 3 Sheets-$heet 2 July15 1924.

; J. w. RECORD EIJECTRICAL MEASURING 1NSIIRUMENT Filed June 26 9fiNVENTOR.

Patented July 15, 1924.

UNITED STATES PATENT OFFICE.-

JOHN W. .RECORD; *F BQWPONyENGLAND.

ELECTRIC/AL MEASURING INSTRUMENT.

flApplica-tion filed June 26, 1922. Serial No. 570,804.

To all whom it may concern:

' Be it knownthat I, Join: \Vnsrn-ionnmnn B-noonn, a British subjectresiding at Bowdon, county of Chester, lflngland, have invented certain.new and. useful Improve- 'ments in Electrical Measuring Instruments,

, of which the following is a specification.

are introduced between the fixed e This invention relates to electricalmeasuring instruments of various types such as ammeters, volt-meters,wattmeters, powerfactor meters, and the like, in which an indicator suchas a pointer has an angular movement across a scale. or a scale movesangulalrly in relation to a fixed point.

The'obj'ect of the invention 18 to provide means'for increasing theangular deflection of the indicators orinters of such instruments to ade ree su antially greater than theangular deflection of the1r movingelements withoutthe introduction of apprecia-' .blefriction such as theintroduction of gearing would give and-which will alsoprovide'for thealtering, modifying or detertermining the character of the scalerequired, enabling it to be expanded or opened up yin some parts anddepressed or closed ot-h'ers, corresponding to given variationsm thequantity being measured' The invention may be applied to instruuponpoising or pivoting of the mtermcdi;

ate elemehtj The invention will be fully described with reference to theaccompanying drawings which show various forms of the invention-diam'anuuaticallv.

i ig. 1 is an illustration ofa known form of moving iron instrument. 1

Fig. 2 is a plan of a moving iron instrument embodying my invention.

Fig. 3 is a sectional elevation of Fig. 2.

Fig. 4 is a sectional diagram of another form of the inventionappliedsto a moving iron instrument at repelling tffpe.

iron instrument through 270.

F ig. 5 is a sectional diagram of another form of the invention appliedto a moving iron instrument of the attraction type.

Fig. 6 is a sectional diagram of another form of the invention appliedto a moving iroln instrument of the attraction type.

*ig. 7 tion applied to an instrument of a moving coil type. i

form of the invention applied to an 'instru ment of a moving coil type.

A common form of a moving iron instrument is shown in Fig. 1,comprising'two pieces'of iron inside a magnetic coil-or sole-' noid A,the piece 13 being fixed and the piece is a diagrammaticview of inven-.-

C being mounted on.a pivoted spindle 0 and carrying a pointerc.

' lVhen the current flows' in the 0011 A, the

two irons B and C are magnetizedand repel I one another, the pivoted oneC being free to move and carry with itthe pointer or,

index finger c','takes. up aposition dependi= I cut upon the strength ofthe current in the coil and the opposing forceof a s ring or equivalentcontrol, the angular efiection seldom exceeds 150 and the maximumdefiection possible cannot exceed 180 because at this angle equilibriumis established between the two irons.

In Figs. 2 and 3 one method is shown of applying the invention to amoving iron instrument. An additional pivoted or moving iron D,fordistinction referred to as a fioatin iron, is nterposed-between theordlnary xed iron '15 and the moving iron 0 carrying the pointer c. Thefloating-iron D is carried on a pivoted spindle (l adjacent to thespindle c. In zero position the fixed iron 13. the moving iron C and thefloating iron D e against one another and when the coil A .1; energized,open out and expand, each repelling the other, and if there is no othercontrolling force equilibrium will be established when the irons becomeequally spaced which will be 120 apart for three irons, apart for fourirons, and so on.

Obviously in a three lIOIl instrument (one fixed, one floating and oneon the pointer spindle) the iron carrying the index would havetraveled-through 240 and-in.the four Theseextreme deflections would,however, be reduced according to.the strengthof control required torestore the moving irons to their initial position. The .pointer 0' isreturned 65 Fig. 8 is a diagrammatic view of another.

ment in which it is possible to obtain a 'de-' flection approaching acomplete circle by the use of only one intermediate or floating elementD. In this construction two coils- A A are arranged in different planesone above the other, and each coil is provided with independentapproximately co-axial spindles d d. The lower coil contains a fixediron B and a moving iron C attached to the spindle d and free to rotate.4 The upper coil also contains two irons D D? the moving iron I), fixedto the upper spindle, to which also is attached the index finger orpointer e, the other a floating iron D carried by an'arm or itsequivalent extended from the lower spindle, and arranged to follow inthe track of the upper moving iron. The same current traverses each coilA A, or one long coil could be usedjnstead of two coils. .As beforeexplained the lower moving iron C will deflect approximately 180 inrespect to the fixed iron B,'and the upper moving iron D and index willdeflect approximately 180-in respect to the floating iron D, but as thelatter has'travelled through 180 in the track of the moving iron C,theindex will have travelled approximately 360 in respect to the fixediron B which was the starting point for them all.

The pointed 0 is returned to zero by a hair spring c or other device inthe ordinary way, the spring being applied to the index spindle or toeach of the co-axial spindles. 1

Air vanes, eddy current discs or other forms of damping not shown, maybe applied to one or more of the co-axial spindles to damp theoscillations and bring the mdex quickly to rest.

A third or fourth tier of similar elements may be employed should agreater movement be required.

The description in Figs. 2, 3, and 4 refers to an instrument of therepelling type, but the invention will be equa ly applicable toinstruments of the attraction type, as shown in Figs-5 and 6.

As shown in Fig. 5 two coils A and A are arranged as before in twoplanes one above the other with co-axial spindles d d carrying movingirons C D which are attracted to the fixed iron B and the floatingiron 1) respectively, the. latter being carried by an arm on the spindleof the moving 1 iron C".

As the iron C moves towards the fixed arm B the floating iron D movesaway from the moving iron D which is attracted to follow it, thus movingthe index pointer considerably further than 180.

In the form shown in Fig. 6 a single coil A is employed with twoco-axial spindles d d carrying the moving irons C D; i The floating ironC is attracted to the fixed iron B and the movin iron D is attracted tothe floating iron C moves towards the fixed iron B? itmoves away fromthe movin iron D .which is attracted to follow it, t us moving the indexpointer considerably further than 180.--

In Fig. 7 one method is shown of applying the invention to moving coilinstruments. The moving coil E is mounted between the poles of a magnetF in ordinary manner with a-spindle e. The spindle e of the moving coilE carries in a higher plane an intermediate or auxiliar coil G in thesame circuit or through which current will flow, and the pointer 1scarried on the spin- As thefloating iron dle of another coil H withinand acted upon by the intermediate coil G thereby giving the desiredincrease of movement to the pointer.

In Fig. 8 another method is shown of applying the invention to movingcoil instruments. The moving coil E is mounted between the poles of amagnet F in ordinary manner with a s indle e. The spindle e of themoving coil carries at its upper end a magnet-K with a second orfloating moving coil' L journalled to oscillate between the poles 10fthe magnet K. The floating coil L carries the index pointer c which willthus swing or move through nearly 360.

What I claim as my invention and desire "to protect by Letters Patentis:-

1. An electric measuring instrument with i a fixedlelement, a movableindicator carrying element and an intermediate floating element, towhich a movement :is imparted from the fixed element and-which in turnimparts'the movement it has received and an additional movement to thepointer carrying element.

2. An electric measuring instrument of the moving iron type constructedwitht'wo o o O 7 coils superimposed, a fixed llOIl 1n the lower L 0011,a moving iron mounted-one spindle within the lower coil, a floatingironwithin the upper coil carried on the. spindle of the moving-iron in thelower coil and a moving pointer carrying iron in the upper coil actedupon by t e floating lIOIl therein.

In testimony whereof I have hereunto set my hand in presence of twosubscribing witnesses.

' JOHN W. RECORD.

Witnesses:

Gnome H. OBnmn, BRIAN OBRIEN.

